Event Flyer  |   Photo Release Form  |  Building Your Bridge  |  Building Your Crane

Results From This Years Event

Event Date: Saturday, November 15, 2008
Time: 8:30 AM-1:00 PM
Location: MOST

Workshop Dates:
Saturday, October 11
Saturday, October 18
Saturday, November 1 during 10:00-11:00 a.m. Need about 15 minutes during this session.
Time: 10:00 a.m.-12:00 noon
Location: MOST

Process:

1. Register your teams, with specific students, online by Friday, October 31. Teams must consist of 2 or 3 students.
2. Materials must be picked up during Bridge Workshops. On these select days, team parents, teachers and supervisors can learn how to design and build a truss bridge, how the bridges are tested, and how the test results are ranked. On site registration is available at the workshops.

Important Dates:
Registration Deadline: Friday, October 31

Materials:
Teams are required to use the balsa wood provided—(15) 2-foot 1/8 inch square pieces. You can use any amount of the wood provided. Glue is provided; however, alternate glues may be substituted. See Building Your Bridge for clarity on this topic.

Competition Levels:
There are three levels teams may enter at:
          Category I (grades 4-6)
          Category II (grades 7-8)
          Category III (grades 9-12)

Category I and II must build a truss bridge. Category III can elect to build a truss bridge and/or a jib crane. The team will compete at the grade level of the most advanced student. For example, a team consisting of two 6th graders and one 7th grader must register as a Categoty II team. Team members normally represent a single school or organization.

Awards:
Every participating student receives a Certificate of Participation and an event T-shirt.

The top three teams in each category receive a plaque and team members receive a ribbon. The plaque should reside at the associated team school.

Questions:
Contact Bobbi Alcock at balcock@most.org or (315) 425-9068 ext. 2146

Structured Support
MOST

L.C. Smith College of Engineering & Computer Science
At Syracuse University

Building Your Bridge - back to top

A. Bridge Contest Summary:
Teams will construct balsa wood bridges to be load tested on the day of the event.

Four awards will be given (1st, 2nd, 3rd, and 4th Place) in each category to the team with the highest score determined from the Bridge Efficiency. Bridge Efficiency is a ratio of how much load the bridge can handle to the mass of the bridge.

Efficiency of your bridge will be determined using the following formula:

The load will be measured in kilograms, while the mass of the bridge will be measured in grams.

Example: If your bridge weighed 22 grams and supported 42 kilograms of weight for 30 seconds during the test, you would calculate efficiency as follows:

One additional award will be given in each category for Bridge Aesthetics.

B. Dimensional Parameters for Bridges:
* Test Block (50mm x 50mm) must be able to pass through bridge.
* Judges will provide blocks to use on day of event.
* Bridges must have a deck structure to support the test platform (provided).
* Bridges shall be loaded only on the bottom of the truss (deck and lower chord).
* Bridge decks must be accessible to test platforms.
* See Diagrams 1 and 2 for a schematic of the testing platforms.

The bridge must be built within these dimensions (See Dimensional Envelope):

* Testing Platform will be provided and should be integrated into your bridge.
** Included in the overall height of the bridge

Note:
It is imperative that bridges are built to the dimensional envelope shown within these rules. Bridges not meeting the geometric requirements will be disqualified.

* Bridges may undergo repairs to meet the dimensional specifications. Only the respective team members shall be allowed to make alterations to the structure.

Blueprints or plans of the bridge will be very helpful prior to final construction of the bridge.

C.Wooden Test Platform:
A 50mm square wooden board will be used during testing to apply stress to the bed of the bridge. Please allow space in your design so that the testing crew can place this in the center of your bridge. Teams can use a 50mm cardboard square to mimic this board.

For Category I and II bridges, the load will be applied to this board from below. The hook, illustrated in Diagram 1, must be able to pass below the bed where the load cell will be connected.

For Category III teams, the applied stress will be applied to the board by a dowel rod from above. Again, make sure the dowel can be centered on the bridge deck from above. See Diagram 2.

Diagram 1

Diagram 2

D. Construction Requirements & Techniques:

• Only the provided materials can be used in the construction of the bridge.
  
• All bridges must contain a truss design element (vertical triagnles).
  
• Splitting of members (wood pieces) is not allowed.
  
• Wood pieces may be bonded together with glue only at joints. If two or more strips of wood are placed parallel to each other, they must be at least the thickness of this page apart from each other.
• No laminating of members (wood pieces) is allowed for Category I or Category II.
  
• Laminating is allowed for Category III teams only.
  
• The term “Laminating” for purposes of this competition is defined as bonding (gluing) together multiple pieces of wood, parallel to one another to create a larger composite truss member.
• See sketch below for allowed types of connections.
  

The Following Types of Connections Must be Considered For Your Bridge:

Tips for Building your Balsa Bridge:

The best advice for building winning structures starts with commitment. Your dedication and attention to detail is the winning combination. The list of tips below will help you succeed, but only if you are dedicated to the project. Be sure you understand the event rules before designing your prototype.

1) Draw your preliminary design with full wood outlines. This should help you to decide whether to use butt joints or lap joints.

2) ALL joints should have absolutely flush surfaces before applying glue.
Any time glue is used as a "gap filler", it dooms the structure! Cut the wood precisely and carefully sand each part so that it fits flush. Then, number each part and use it as a template to make numbered duplicates in assembly sequence (i.e.: two for bridges, four for towers).

3) Structures are symmetric. When building a bridge or a tower with two or four sides, build the two primary sides one on top of the other. Once the first side is built, cover it with wax paper and build the second side directly on top of the first. This helps insure the structure’s symmetric integrity.

4) Most competitions require these structures to be weighed. Up to 20% of the structure's mass may be from over-gluing. Adhesives do not work better when they are drooled all over the structure. Use the adhesives sparingly. Any more than a translucent, moist surface becomes wasted, excess mass.

5) When building a balsa wood structure, pre-test all the strips for tensile strength before assembly. A simple deflection test works best. Anchor half of the strip on a surface and ballast the free end using clay on a bent straight pin. Use a simple gauge to categorize the strips. Group similar tensile strengths together. The strips that deflect the least are the strongest. Use those for the longest pieces. The ones that defect the most use as the shortest pieces. When the structure is finished, it should have a relatively consistent load carrying capability.

The above tips can also be viewed at the following URL:

http://www.midwestproducts.com/structtips.htm

E. Recommended Tips for Contructing Your Bridge

Four views should be drawn:
1. END VIEW
2. SIDE VIEW
3. ROADBED
4. TOP VIEW

Recommended Construction Materials & Tools:

• Building Board
• Straight Pins, to hold pieces in place as glue dries
• Single Edge Razor Blade or X-Acto® knife for cutting
• Waxed Paper to cover the plan (blueprint) as you build on top of it
• Ruler or other device for measuring
• 15 pieces of wood and a 2/3 oz. bottle of glue (supplied)

Results of the 2008 Event
Category I | Category II | Category III

Category I Results